Comcast expands IPv6 trial

Carolyn Duffy Marsan, Network World |
June 6, 2011

Comcast has expanded its IPv6 trial, adding hundreds of cable modem subscribers in the San Francisco, Philadelphia, Chicago and Miami areas to participants in Littleton, Colo., that have been operational all year with this next-generation Internet service.

IPv4 uses 32-bit addresses and can support 4.3 billion devices connected directly to the Internet, but IPv6 uses 128-bit addresses and can connect up a virtually unlimited number of devices: 2 to the 128th power. IPv6 offers the promise of faster, less-costly Internet services than the alternative, which is to extend the life of IPv4 using network address translation (NAT) devices.

One major stumbling block for IPv6 deployment is that it's not backward compatible with IPv4. That means carriers such as Comcast and website

operators such as Google have to upgrade their network equipment and software to support IPv6 traffic.